Posted on 08/09/2018 9:09:56 AM PDT by BenLurkin
The NASA manager overseeing development of Boeing and SpaceX’s commercial crew ferry ships says the space agency has approved SpaceX’s proposal to strap in astronauts atop Falcon 9 rockets, then fuel the launchers in the final hour of the countdown as the company does for its uncrewed missions.
The “load-and-go” procedure has become standard for SpaceX’s satellite launches, in which an automatic countdown sequencer commands chilled kerosene and cryogenic liquid oxygen to flow into the Falcon 9 rocket in the final minutes before liftoff.
“From a program standpoint, we went throgh a pretty extensive process where we laid out the different options for loading the crew, and assessing how the vehicles have been designed, and what the trades were,” said Kathy Lueders, NASA’s commercial crew program manager, in an interview Friday. “That came to the program in June, and after looking at it, we felt like the current baseline plan for how SpaceX plans to load the crews meets our requirements.”
Other liquid-fueled rockets, such as United Launch Alliance’s Atlas 5 launcher, typically receive their propellants earlier in their countdowns. The Atlas 5, which will be used to launch Boeing’s CST-100 Starliner capsule, consumes the same propellants as the Falcon 9.
(Excerpt) Read more at spaceflightnow.com ...
Gus Grissom was unavailable for comment ...
Probably no riskier than other methods.
Read the part of the article about the abort system and the new COPV.
See post #4.
The rocket wasn’t even fueled when the Apollo 1 fire happened.
*ping*
I am all for the commercial exploration / exploitation of outer space. Yet the question remains: Elon Musk.
The Apollo 1 fire happened because the combination of 100% oxygen atmosphere, way higher than normal pressurization and way too much exposed flammable material result in a fire that killed the astronauts very quickly. The Russians found out the hard way some years earlier in a space simulator when a fire broke out in a 100% oxygen atmosphere.
Not sure if that is a good analogy. I do remember the event. Horrible. Just horrible.
The portrayal of it in “From The Earth to The Moon” miniseries was pretty wrenching, IIRC.
I merely point out that astronauts have burned to death on the launch pad before. Even before fueling.
If they’ve done sufficient risk mitigation (and I imagine they have) then this plan isn’t necessarily bad. But I’d be nervous being strapped in the seat while they carefully pump rocket fuel into the thing. What could go wrong?
Ah. I didn’t get that. I understand how that is a concern.
I assume far more accidents occur during takeoff and ascent than during the filling of tanks, but...I don’t follow that aspect very closely.
My wife has grown to hate it when I say that in the appropriate tone of voice...
I have grown to hate seeing that phrase posted on FR, almost always by people with ZERO knowledge of the subject at hand.
I ask myself this with no hint of derision or sarcasm, because I truly don't know. Is it safer to fuel up hours or only moments before launch?
Liquid propellants warm up and bleed off constantly on the pad, that's a potential disaster in itself. For a long wait, enough fuel could escape that more is needed to complete the mission. You have to add fuel on the pad, do you evacuate the capsule? If you do, now you're really behind, you miss your window.
You gotta think about stress on the rocket, condensation and ice buildup too. Maybe the minimum time is actually safer, even if it's a risk to load a manned rocket. Which risk is greater?
You don't suppose, perhaps, that the engineers at SpaceX have already thought about that, do you?
As posed on this forum, the question is almost invariably posed in ignorant derision. It has grown tiresome.
I actually read the article. I know: Heresy and Blasphemy!!!
Reasons for fueling immediately before launch are given ... and are interesting. The Falcon-9 does some things a little differently from older rockets.
Yeah but in this case it was posted with a image of EXACTLY the subject at hand.
“From a program standpoint, we went throgh a pretty extensive process where we laid out the different options for loading the crew, and assessing how the vehicles have been designed, and what the trades were,”
When this comes from the organization that signed off on the Apollo 1 design, the SST design (major contributor in both shuttle losses), the report on SRB damage in cold weather (prime cause of Challenger), plus the crappy insulation on Columbia.... Well lets just say I hope their ‘trades’ were weighted well.
“Reasons for fueling immediately before launch are given ... and are interesting. The Falcon-9 does some things a little differently from older rockets. “
Before you keep throwing around ‘ignorant derision’...Yeah the SpaceX engineers considered it and went in favor of performance over extra safety. And a rocket went BOOM. You beat around bush calling the reason ‘interesting’ but the simple fact is they chose a deign that gets a bit more performance for a bit more operational risk. And that explosion proves they did not weight that risk high enough or do their do diligence in making the design robust the first time. Had that rocket not blow we very well might have had a crew on top of that same design. They probably would not have redesigned the tank if that one had not blown up.
So it is not ‘ignorant derision’ that leads some of us to question this trade off. Some of us are paying attention. And yes I know the Dragon escape systems are rated to get clear of an explosion like that. I am an engineer in the aerospace sector so I can tell you we don’t consider something safe just because people survive when it BLOW UP. Using the escape engines is inherently risky.
Sometimes, a picture is worse than worthless.
This is an example of the latter. Did that picture tell you anything about the cause of that loss? Did that picture tell you if the launcher has been redesigned to fix those causes? NO. It did not. It was and is a worse than worthless post.
I see you're about to take an airplane trip.
What could possibly go wrong?
I see you're about to drive your car.
What could possibly go wrong?
I see you insist on staying home.
What could possibly go wrong?
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